We propose to use DNA microarrays to examine translational regulatory pathways in cells infected with influenza virus or subjected to endoplasmic reticulum (ER) stress. These studies are an outgrowth of findings made under the parent award entitled: "Translational Control in Influenza Virus Infected Cells" (R01 AI22646, Michael G. Katze, P.I.). In the parent award, we are working to define the role of the cellular RNA-binding protein, GRSF-1, in the selective translation of influenza virus mRNAs. We propose to expand this effort by using DNA microarrays to identify cellular mRNAs that bind specifically to GRSF-1. There is currently no information regarding the role of GRSF-1 in the translation of cellular mRNAs, and the identification of mRNAs that bind to GRSF-1 will yield insight into the nature of the GRSF-1 binding site, the types of mRNAs that contain this site, and whether these mRNAs escape the shutoff of cellular mRNA translation in influenza virus infected cells. An additional aim of the parent award is to characterize the stress-response pathway activated by influenza virus to regulate the interferon-induced protein kinase, PKR. A critical component of this pathway is the cellular PKR inhibitor, the molecular co-chaperone P581PK. Under the parent award we have demonstrated that the P581PK gene is induced during ER stress and that P581PK interacts with the elF2-alpha kinase, PERK. We have also constructed P581PK knockout mouse embryonic stem cells to study the role of P581PK in stress-response pathways. We now propose to use DNA microarrays to examine cellular gene expression in wild type and P581PK knockout cells to examine the effects of deletion of P581PK on the cellular response to influenza virus infection or ER stress. These studies will yield new information on the roles of P581PK and translational regulation in cellular stress-response pathways. The proposed studies make use of technologies not available at the time of the parent grant award and will allow us to capitalize on recent findings and extend our studies in new directions.